NAME

Log::Log4perl::Lazy - Lazily evaluate logging arguments

VERSION

Version 0.02

SYNOPSIS

    use Log::Log4perl::Lazy;
    DEBUG 'debug message';

EXPORT

TRACE, DEBUG, INFO, WARN, ERROR, and FATAL

DESCRIPTION

This module is an extension of Log::Log4perl.

You can simply write something like this:

    DEBUG 'obj = '.slow_func($obj);

where the argument of the DEBUG subroutine will be *lazily* evaluated.

This means, if the DEBUG level is not enabled for the current package, the argument is not evaluated at all. As a result, slow_func is not called when it is unnecessary.

It allows you to avoid writing the if-statements everywhere like this:

    use Log::Log4perl qw(get_logger);
    my $logger = get_logger;
    $logger->debug('obj1 = '.slow_func($obj1)) if $logger->is_debug;
    $logger->debug('obj2 = '.slow_func($obj2)) if $logger->is_debug;
    $logger->debug('obj3 = '.slow_func($obj3)) if $logger->is_debug;

while you don't need to worry about the performance overhead of slow_func in the production code.

LIMITATIONS

The current version does not support the object-oriented interface.

With the non-OO subroutines, although Log::Log4perl allows you to pass as many arguments as you want, this module only allows you to pass one argument.

    # This does not work with Log::Log4perl::Lazy.
    DEBUG 'a', 'b', 'c';

    # You should concatenate the argument into one.
    DEBUG 'a'.'b'.'c';

In the above, if the debug level is not enabled, the concatenation will not take place, so no worries about overhead!

AUTHOR

Mahiro Ando, <mahiro at cpan.org>

BUGS

Please report any bugs or feature requests to bug-log-log4perl-lazy at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Log-Log4perl-Lazy. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Log::Log4perl::Lazy

You can also look for information at:

ACKNOWLEDGEMENTS

Log::Log4perl, Params::Lazy

LICENSE AND COPYRIGHT

Copyright 2013 Mahiro Ando.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.